Air-compressing device.



Nol 7l3,848.

- Patnted Nov. la, |902..

J. H. BuLLAnn.

AIR CMPRESSING DEVICE.

Y (Application led Nov. 25, 1901.)

'lill/[All IIL ll (No Model.)

limiten Sintes Parent Orrice.

JAMES II. BULLARD, OF SPRINGFIELD OVERMAN AUTOMOBILE COMPAN CORPORATION.

AIR-COMPRESSING DEVICE.

SPECIFICATION forming part of Letters Patent No. 713,848, dated November18, 1902. Application filed November 25, 1901. Serial No. 83,593. (Nomodel.)

To all whom it may concern:

Be it known that I, JAMES H. BULLARD, a citizen of the United States ofAmerica, residing at Springfield, in the county of Hamp den and State ofMassachusetts, have invented new and useful Improvements inAir-Coinpressing Devices, of which the following is a specification.

This invention relates to air-compressors Io and means for controllingthe delivery of air therefrom, the object of the invention being toprovide means for rendering ineffective the action of the piston in acontinuouslyrunning pump when the air in a receivingr5 tank attains acertain pressure; and the invention consistsin the construction fullydescribed in the following specification and particularly pointed out inthe claim.

In the drawings forming part of this appli- 2o cation, Figure lis a sideelevation of the pump embodying my invention, but it is shown as formingpart of a feed-water pump and is actuated by the same means as thelatter. Fig. 2 is an end elevation of Fig. l. Fig. 3

is a top plan view ot Fig. l; and Fig. 4 is an enlarged sectionalelevation through one end of the air-compressor, showing the air-compressing cylinder and its controlling devices and showing thewater-feeding cylinder.

In Fig. l of the drawings the two air-pumping cylinders (indicated by 7land 72) are shownin side elevation. The pistons of these cylinders-oneof which is shown in Fig. 4 have a common piston-rod 73, which isparallel with and vertically over the piston of the watercylinders,which piston is indicated by 74 and the water-cylinders by 75 and 7G. Arigid connection 77 secures these two piston-rods together, as shown inFigs. l and 3,

4o both being driven by a connecting-rod 78, extending from saidconnection 77 to a pin on the side of a gear 79, supported to mesh witha second gear 80, fixed on the axle of the vehicle or some otherconvenient rotating part thereof.

At each end of the pump there is cast integrally with the cylinders avertical cylindrical casing 8l, which is bored out axially, as shown inFig. 4, and in which bored-out 5o portion there is provided a seat 82for the ball 83 and another seat 84 for the ball 85, these ballsconstituting check-valves,between which there is a port 86, leading intothe aircylinder. An eduction-pipe 87 leads out of the upper end of saidcylindrical casing, and an induction-port 88 (see Figs. l and 4) extendsthrough the wall of said end casing and leads into the interior thereofbeneath the seat of the ball 85. Upon the suctionstroke of the pistonair enters through the 6o induction-port, passes upward under the ball85, and into the cylinder through the port S6. Upon the forcing-strokethe air so drawn in is forced out through the same port at which itenters the cylinder and lifting the ball 83 65 from its seat passes upthrough the eductionpipe, which leads to the air-reservoir.

Parallel with the centrally-bored-out portion of the cylindrical casing8l there is an air-passage S9, extending from one end to the 7o other ofthe casing, and at each end of this -air-passage there is a port leadinginto the central bored-out portion of the casing. The port 90 leads fromthe chamber in which is located the ball 83, and the second port 91 at75 the bottom of the passage leads into a chamber located below the ball85 and the induction-port. This chamber, also cylindrical in form incross-section, has located therein a plunger 92, having a stem thereonextending 8o upwardly approximately to the under side of the ball S5.Between the top of said plunger and the bottoni of the shoulder formedby the seatof said ball there is a spiral spring which normally holdsthe plunger 92 down against 85 the top ofan inverted expansible sack93,whose open end is secured near the lower end ot the chamber in whichsaid plunger is located by Va ring expanded against the wall of thechamber, as shown, or otherwise. N ow when the 9o back pressure on theeduction-pipe exceeds the resistance of the spring 94, which holds theplunger away from the ball 85, said sack will by the pressure of airentering it through the port 90, the passage 89, and the second 95 portin the lower end of said passage be expanded vertically to a sufcientdegree to raise the plunger 92 and force the ball 85 away from its seatand hold it out of contact therewith during the maintenance of saidexcessive Ioo pressure. The result of this operation will be that theair drawn in through the induction-port will on the forcing-stroke ofthe piston pass out 'again through the same induction-port, the ball 83being firmly held to its seat by the pressure from the reservoir. Assoon as the pressurein the latter, however, drops sufficiently to permitthe ball 85 to seat itself air will be again forced into the reservoirto restore the pressure therein to its maximum. This construction (shownin Fig. 4) is common to both of the air-cylinders of the pump, theeduction-pipes of both running into a common branch connecting with theair-reservoir.

Having thus described my invention, Wha't I claim, and desire to secureby Letters Patent of the United States, is-

A pump consisting of a cylinder, a valvechest therefor, an induction andan eduction pipe in said chest, a check-valve in the latter for each ofsaid pipes and opening in the same direction, a single port for thecylinder located between the check-Valves and serving both for aninduction and an eduction port; a passage outside the valve-chestcommunicating with opposite ends of the latter, and in communicationonly with the eduction-pipe, and an expansible and retractable sack inproximity to the check-valve for the inductionpipe, adapted to beiuiated by back pressure from the eduction-pipe whereby an excess ofpressure in the latter will effect the lifting of the check-valve in theinduction-pipe from its seat, to render the pump ineffective.

JAMES H. BULLARD.

Witnesses:

W. H. CHAPIN, K. I. CLEMoNs.

